With known products, such as the 3RW40 Size S6 (MLFB: 3RW4055) soft starter or 3RT1023 Size S0 contactor made by Siemens AG, the yoke, exactly like the solenoid coil and coil body, is fixed to the housing of the switching device by a so-called yoke suspension. The yoke suspension includes sprung clamps, which encompass the yoke, for example, and which engage with the housing top part. FIG. 5 shows a switching device 110 of this kind in a rough schematic view. A coil 100 is fitted on a housing top part 102, e.g. clipped onto the housing top part. A yoke 104 is placed on the coil 100. Yoke holder 112 associated with yoke 104 is likewise fitted to the housing top part 102 in that the yoke holder 112 is sprung onto the housing top part with the help of sprung connectors 114. The coil 100 and yoke 104 are therefore both held to the housing top part.
It is also known to place the yoke on the coil body and to provide an insert part on the side of the yoke facing away from the coil body. All three components are then fixed between a housing top part and a housing bottom part, which are clipped together. In doing so, the housing top part can be formed in one piece with the coil body. An arrangement of this kind is shown in FIG. 4 as switching device 110 in a rough schematic view. Here, a coil 100 is fitted on a housing top part 102 or designed in one piece with said housing top part. A yoke 104 is placed on the opposite side of the coil 100. An insert part 106 is placed against the yoke 104. Coil 100, yoke 104 and insert part 106 are clamped or securely fixed in position between the two by means of a housing bottom part 108, which is clipped onto the housing top part 102. The remaining components of the switching device 110 are not shown in FIG. 4 for the sake of clarity.
The disadvantages of the known solutions are that, for example, sprung hooks for fixing the yoke must be provided by means of housing parts in the device, that the part complexity is high, as separate parts are necessary for clipping, that the yoke holders have an additional space requirement in the device, and that assembly errors, e.g. forgetting a yoke holder or a holding clamp, can occur.